Using a representative sample of married dual-earner couples in Japan, this study analyzes the conditions under which husbands contribute to household tasks conventionally performed by wives. Survey data are analyzed using regression procedures with husbands’ involvement in housework (meal preparation, laundry, and bathroom clean-up) treated as a major dependent variable, and family networks, relative resources, practicality, ideology, and work environment treated as major explanatory variables. Although Japanese husbands’ overall performance in these household tasks is minimal, I found that these men participate in routine housework more frequently if their family support networks are not readily available, if they are employed fewer hours, if they hold more egalitarian gender ideology, if their wives earn a larger share of the family income and the husband-wife age gap is greater, and if their wives’ commuting hours are longer. Theoretical explanations for the observed findings are discussed and the directions for future research are suggested.